Seahorses are entirely non-verbal (meaning they make no known communicative sounds) but that doesn’t mean they don’t communicate. On the contrary, seahorses develop complex and important relationships that range from aggressive to friendly and romantic, and they spend a lot of time interacting with other seahorses in their environment.
Although adult seahorses don’t “parent” the way mammals do, they show remarkable tolerance for juvenile seahorses. Small seahorses often “hitch” to larger ones, or follow the adults around, observing and copying behaviors. Adult seahorses tolerate the babies’ presence, and seem to give them far more leeway when it comes to “uncomfortable” grabbing than they do when another adult hitches onto a tail, neck, or snout. While adult seahorses will shake babies off if they get too grabby, adults seem to understand that baby seahorses’ hitching is an attempt to feel secure and not a show of aggression (as it can be when adults grab one another).
Curiously, the adults show similar patience with my smallest seahorse, Magellan, who has a physical disability that stunted his growth. Although the same age as the larger seahorses, Magellan remains about the size of a six-month old juvenile, and the adults allow him to hitch to them, grab them, and interact with them much as an immature seahorse would.
I’m not sure whether they understand that he has a disability or (more likely) simply “see” him as a baby due to his size, but they show him unusual patience and let him behave in ways they do not tolerate from the other adults.
Older seahorses frequently “hold tails” as a sign of affection, and seahorse courtship rituals involve a lot of tail-twining and swimming in pairs. Mates will also hitch to one another, or to the same object, keeping their bodies close together in what can only be a show of affection.
Unmated adults also interact with regularity, communicating through eye contact as well as touch.
In some cases, seahorses use their tails to establish dominance or show aggression–mostly by hitching to another seahorse’s head or neck until the less-dominant seahorse surrenders and swims away. While seahorse-to-seahorse aggression isn’t common in uncrowded conditions with plentiful food (at least among the Hippocampus erectus species that I keep) it does occur, particularly where seahorses have conflicts over mating or, less commonly, a favorite hitch.
It’s impossible to know, for certain, exactly what seahorses think or what they “say” to one another in their frequent interactions. We can guess–and anthropomorphize–but their true communications will always remain a secret for them alone.
Wouldn’t it be nice if we could hear what they have to say?